Below are excerpts from the review:
The ddHiFi TC44A offers a pretty natural presentation for such a miniaturized DAC/AMP adapter with 4.4mm Single Ended output. It shows a slightly warmer than neutral tonality, while it has low amount of coloration that is not overdone. The general atmosphere is pretty transparent and airy, while the bass is produced with a good level of authority. The midrange on the other hand is shown with a natural sense of transparency and resolution, while the treble range has a decent grade of clarity and definition for DAC/AMP adaptor at this price tag.
From: Moonstar Review